Current biospsy devices and methods do not consistently provide an adequate sample to diagnose uterine abnormalities. For instance, if a cancer exists on the inside of the uterus, i.e. the endometrium, current devices and methods may miss the cancer and preclude an accurate diagnosis. To ensure an adequate and accurate specimen currently often requires a painful and dangerous series of procedures.
For example, the Cook Medical Tao Brush™ I.U.M.C. Endometrial Sampler, and the Pipelle endometrial biopsy device (See, Sierecki A R, Gudipudi D K, Montemarano N, Del Priore G., “Comparison of endometrial aspiration biopsy techniques: specimen adequacy.” J Reprod Med. 53(10):760-4, 2008 Oct.), expressly incorporated herein by reference.
The currently available options fall into two categories. The first are devices and methods that can be used in the office. These are usually thin devices 2-5 mm diameter that rely on either a weak suction or a disruption of the uterus. These are relative safe options but are not considered sufficiently accurate. The other category consists of larger devices that require more analgesics and even an operating room. This category includes the traditional dilation and curettage, i.e. D&C, and hysteroscopy. This category is more dangerous and painful than the first category. Neither category consistently gives an adequate, accurate and safely obtained sample and diagnosis in every case.
Endometrial sampling has become an integral part of the workup of pre-menopausal and postmenopausal women who are having abnormal uterine bleeding. Approximately over one million endometrial sampling procedures are done in the United States annually. Of the women born today, 2.45% (1 in 41) will be diagnosed with cancer of the uterus sometime during their lifetime. Therefore, theoretically 1 in 41 women will need an endometrial biopsy sometime in their lifetime.
Despite the large number of endometrial biopsies performed, limited information is available on the best technique to use with an aspiration type endometrial biopsy device (e.g. Pipelle, Cooper Surgical, Inc. Trumbull, Calif.). A slight difference in sensitivity and specificity of any screening procedure will have a great impact on the general population in identifying cancer especially for a test performed so frequently.
Specimen adequacy is the important factor for a procedure to be accurate in detecting abnormal pathology, especially a potential malignancy, precancerous or early cancer lesion. Different endometrial biopsy techniques are used with the aspiration device; e.g. “cork-screw”, “D&C”, or a combination of both with little objective data on what technique is best.
Most tests have an inherent sensitivity and specificity. However alteration in technique can be an important part of the test performance. We noticed that some members of our faculty group practice had different techniques based on intuition, e.g. povidone-iodine cleansing before endometrial biopsy. A literature reviewed and survey of the participating clinicians could not come up with a published evaluation of the different aspiration biopsy techniques used. We felt that the potential influence of these different techniques on the test characteristics of a test done more than one million times each year was important enough to begin an investigation of this area using a convenient sample and a retrospective chart review.
Based upon our analysis, the combined technique is significantly better than using either technique alone. Due to the large number of endometrial biopsies performed each year, even a small difference in test characteristics can have significant clinical ramifications.
Endometrial biopsy in the office setting, which consists of endometrial sampling using an aspiration biopsy device, has been shown to have sensitivity equivalent to that of dilatation & curettage (D&C). Its advantages include lower cost, it does not require anesthesia and it can be carried out in an office setting. Analyses have shown that a D&C is more costly and no more accurate in diagnosing endometrial abnormalities than the aspiration biopsy device. Aspiration biopsy device has been shown in repeated controlled clinical trials to be as effective as a D&C in diagnosing malignancy.
Although the aspiration biopsy device can detect cancer accurately, they may not able to detect tumors localized to a polyp or a small area of endometrium. Because of this variable and others, the sensitivity of an aspiration biopsy device in detecting uterine cancer varies in studies from 67% to 100% with an overall specificity of 100%. Huang et al. study found that an aspiration biopsy device had a sensitivity of 99.2% in pinpointing high-grade cancer and a sensitivity of 93% in detecting low-grade malignancies; the sensitivities as defined for D&C were 100% and 97% respectively. Low cost and accuracy dictate that an office aspiration biopsy device should be used as the frontline test for endometrial sampling and the detection of endometrial cancer.
The National Cancer Institute (NCI, 2008) has stated that there is insufficient evidence to establish whether a decrease in mortality from endometrial cancer occurs with screening by endometrial sampling. The NCI notes that based on solid evidence, endometrial biopsy (sampling) may result in discomfort, bleeding, infection, and in rare cases uterine perforation. In addition, risks associated with false-positive test results include anxiety and additional diagnostic testing and surgery. Furthermore, endometrial cancers may be missed on endometrial sampling.
Endometrial sampling by means of biopsy for histological examination in the diagnostic evaluation of abnormal uterine bleeding in women suspected of having endometrial hyperplasia or endometrial carcinoma is a minimally invasive alternative for dilatation and curettage (D&C) or hysteroscopy. The Pipelle endometrial sampling device is the most popular method for sampling the endometrial lining (Guido, 2008). Various types of brushes have also been used for endometrial sampling. Although the brush appears to be as effective or better than other blind methods of endometrial sampling, these devices have been evaluated in only a few studies with small numbers of subjects (Critchley, et al., 2004; Yang, et al., 2002; Del Priore et al., 2001; Yang & Wan, 2000; Maksem, et al., 2000). In one of the larger comparative trials, 101 women (aged 35 to 86 years) with clinical indications for endometrial biopsy underwent a brush biopsy (Tao Brush, Cook OB-GYN, Bloomington, Ind.) and a Pipelle biopsy (Cooper Surgical, Shelton, Conn.) during one office visit. Twenty-two had cancer or atypia, the others had benign diagnoses. When correlated with the final diagnosis, sensitivity for the Tao Brush and Pipelle were 95.5% and 86%, respectively, and specificity was 100% for both (Del Priore, et al., 2001).
According to the company's website (Gynecor™, Glen Allen, Va.), the TruTest™ for total uterine testing is the first test that is able to detect endometrial and cervical cancer, HPV, chlamydia and gonorrhea from the same specimen. Using the Tao Brush, a sampling of the uterine lining is taken and the brush is sent to Gynecor™ for both histology and cytology examination. The testing kit provided by Gynecor has one Tao Brush (used for the collection of endometrial tissue) and two cytobrushes (one is used to clean mucus and debris from the cervix and the second is used for enhanced cell and tissue collection from the squamo-columnar junction of the uterine cervix). The Tao Brush is an FDA, Class II device.
The use of histology for endometrial examination depends on having enough tissue to yield an accurate test result. However, a tissue specimen is sometimes hard to collect, especially in post-menopausal women. Gynecor fixative can be used for both histology and cytology. According to Gynecore's website, “Cytologies are very important because they add about 20% more information than is obtained with just the histology. Using this method, Gynecor has been able to diagnose ovarian carcinoma in transit, endometrial intraepithelial neoplasia and endometrial intraepithelial carcinoma.”
In a feasibility study, Maksem, et al. (1997) compared the cytologic diagnosis to the histologic diagnosis of endometrium collected from 100 hysterectomy specimens using the Tao Brush and the CytoRich fixative system. Interpretative algorithms that translate histopathologic to cytopathologic diagnoses were used. The authors reported that cytology separated benign endometrium, low-grade (non-atypical) hyperplasia, high-grade (atypical) hyperplasia/FIGO Grade I adenocarcinoma, and higher-grade carcinomas from one another. Endometrial atrophy was diagnosed in 3 patients whose histology showed clinically asymptomatic, benign fibrous endometrial polyps. A low volume of abnormal cell aggregates interpreted as endometrial intraepithelial carcinoma was detected in 1 patient whose initial histology was reported as simple hyperplasia, but whose histology on review after p53 staining revealed intraepithelial surface cancer. In the remaining 96 cases, the cytologic diagnosis consistently represented the histologic diagnosis of the hysterectomy specimen. On a case-by-case basis, any one cytology slide accurately represented the diagnosis of the other cytology slides. The authors concluded that endometrial brushing with suspension fixation is (i) uniform, (ii) three-dimensional structures among cell aggregates are preserved, which allows pattern-based histologic diagnostic criteria to be applied to cytologic samples, and (iii) only a limited number of slides need to be examined.
Van den Bosch, et al. (1998) evaluated the value of cervical cytology in menopausal women at high risk for endometrial disease in 128 consecutive menopausal women presenting with uterine bleeding (n=116) or in whom endometrial cells were found on a previous cervical cytology smear (n=12). An endo- and ecto-cervical smear was taken before hysteroscopy with curettage and the results of the cervical cytology were compared with the endometrial histology. Endometrial carcinoma was diagnosed by endometrial sampling in 6 women. In 2 of these cases cervical smears did not contain endometrial cells. The presence of endometrial cells on ecto-cervical cytology showed a sensitivity of 67% and a specificity of 78% for endometrial carcinoma versus 80% and 76%, respectively, for endo-cervical cytology. The positive predictive value for endometrial malignancy of the presence of endometrial cells on cervical cytology ranged between 13% and 17%. The presence of atypical endometrial cells on cervical smear was associated with endometrial malignancy in almost half the cases. The authors concluded that cervical cytology is of limited value in the diagnosis and the management of post-menopausal endometrial disease.
Dijkhuizen, et al. (2000) performed a meta-analysis to assess the accuracy of endometrial sampling devices in the detection of endometrial carcinoma and atypical hyperplasia. The authors searched the literature for studies published between 1966 and 1999 that compared the results of endometrial sampling with findings at D&C, hysteroscopy, and/or hysterectomy. They found 39 studies that included 7,914 women. For each study, the number of patients in which endometrial sampling failed as well as the sensitivity and specificity for the detection of endometrial carcinoma and atypical hyperplasia was calculated. The detection rate for endometrial carcinoma was higher in post-menopausal women compared with pre-menopausal women. In both post-menopausal and pre-menopausal women, the Pipelle was the best device, with detection rates of 99.6% and 91%, respectively. For the detection of atypical hyperplasia, there was only one study that reported explicitly on post-menopausal women, thereby hampering the possibility of subgroup analysis. Again, the Pipelle was the most sensitive technique with a sensitivity of 81%. The specificity of all devices was greater than 98%. The authors concluded that endometrial biopsy with the Pipelle is superior to other endometrial techniques in the detection of endometrial carcinoma and atypical hyperplasia. The accuracy of the Pipelle is higher in post-menopausal women compared with pre-menopausal women.
Maksem (2000) reported performance characteristics of the ability of the Tao Brush in recognizing histological patterns in cytology preparations of endometrial brushings (n=113). Correlative tissue examinations comprising Pipelle (Prodimed, Neuilly-en-Thelle, France) biopsy, hysteroscopy and biopsy, D&C, and hysterectomy were available at for 59 cases. In 42 cases, cytology diagnoses could be compared to histology diagnoses. Twenty-five of 63 normal brushings were followed up; 14 were normal. Eleven Pipelle biopsies of cytologically atrophic endometrium were quantitatively limited and insufficient for diagnosis. Thirty-seven cases were abnormal, and 15 of these showed nuclear anaplasia. Twenty-eight of the abnormal cases were followed up. All correlative tissue examinations confirmed an abnormality. All 15 cases with nuclear anaplasia showed significant histopathology comprising atypical endometrial hyperplasia, endometrial intraepithelial neoplasia (EIN), endometrial intraepithelial carcinoma (EIC), and invasive adenocarcinoma. There were 13 inadequate endometrial brushings. Three cases had insufficient cellular material. The remaining 10 cases were cellular but were mainly cervical/endo-cervical samples. Two of the cellular cases resulted from clinicians failing to replace the protective sheath over the brush bristles before removing the Tao Brush from the endometrial cavity. The remaining 11 cases resulted from inaccessibility of the uterine cavity due to a tight or stenotic cervix. The author concluded that (i) the Tao brush is a reliable uterine sampling device for outpatient assessment of the endometrium of women with patent cervices, (ii) endometrial cytology accurately represents atrophic endometrium, (iii) it is an effective case-finding tool for EIN and EIC, and (iv) women with tight or stenotic cervices are poor candidates for endometrial brushing, and may experience pain if the procedure is attempted.
In a case series on the use of the Tao Brush for endometrial biopsy, Wu, et al. (2003) reported that the sensitivity and specificity in identifying endometrial cancer was 100% and 96%; however, diagnosis relied mainly on histologic evaluation of hematoxylin and eosin-stained tissue sections and assessment of specimen adequacy was important when interpreting Tao Brush biopsies.
In an unblinded randomized trial, Critchley, et al. (2004) compared 3 outpatient methods of endometrial evaluation in terms of performance, patient acceptability and cost-effectiveness. Women referred for investigation and management of abnormal bleeding between January 1999 and May 2001 were evaluated using blind biopsy alone, hysteroscopy with biopsy, ultrasound evaluation including transvaginal ultrasound, and, in the low-risk group, the option of no investigation. Within this design, two devices for obtaining endometrial biopsy were compared, the Pipelle sampler and the Tao Brush. Minor adverse events (e.g., shock, patient distress) did not occur for ultrasound, but occurred in 16% and 10% of women for hysteroscopy and biopsy procedures respectively. Pipelle biopsy provided an acceptable endometrial sample for 79% of moderate-risk women, but only 43% of high-risk women. The Tao Brush gave similar performance in moderate-risk women (77%), but was more successful than the Pipelle sampler in post-menopausal (high-risk) women (72%).
To determine the performance characteristics of endometrial cytology for the detection of malignancy and atypical hyperplasia using liquid-based cytology specimens collected with the Tao Brush sampler, Kipp, et al. (2008) obtained brushings of the endometrial cavity from 139 hysterectomy specimens before routine histopathologic evaluation. Cytology specimens were fixed in PreservCyt and processed using ThinPrep technology. Cytology diagnoses were classified as non-diagnostic, negative, atypical, or positive for malignancy. Histopathologic findings were used as the gold standard for determining the performance characteristics of cytology. Histopathologic results from the 139 patients included 81 (58%) endometrial cancers, 7 (5%) complex hyperplasias with atypia, 2 (1%) complex hyperplasias without atypia, and 49 (35%) patients with benign histology. The number of specimens diagnosed cytologically as positive, atypical, negative, or non-diagnostic was 60 (43%), 40 (29%), 37 (27%), and 2 (1%), respectively. The overall sensitivity and specificity of cytology for detecting endometrial cancer and atypical hyperplasia were 95% and 66% when atypical cytology specimens were considered positive. The authors concluded that direct endometrial sampling by liquid-based endometrial cytology collected with the Tao Brush sampler produces specimens that contain cellular material that may be identified as endometrial cancer or atypical hyperplasia; however, both atypical and positive cytology diagnoses are indicators for triage to more specific methods of diagnosis.
Williams, et al. (2008) evaluated factors affecting the adequacy of pipelle and Tao Brush endometrial sampling. Women referred to an outpatient clinical for assessment of abnormal vaginal bleeding (n=200) were assigned to one of two risk groups: “high risk” for post-menopausal women and “moderate risk” for pre-menopausal women aged 40 years or older or with other risk factors. Women in each risk group had both Tao Brush and Pipelle biopsy and were then randomized to have either hysteroscopy and/or transvaginal ultrasound. Nulliparity was associated with failed insertion for both the Tao Brush and Pipelle (p<0.001). Among post-menopausal women, inadequate samples were associated with the Pipelle (p<0.001). Among pre-menopausal women with nulliparity, both the Tao Brush and Pipelle were associated with inadequate samples (p<0.001). A significantly greater proportion of women preferred the Tao Brush to the Pipelle.
Outpatient endometrial biopsy has a high overall accuracy in diagnosing endometrial cancer when an adequate specimen is obtained. A positive test result is more accurate for ruling in disease than a negative test result is for ruling it out. Therefore, in cases of abnormal uterine bleeding where symptoms persist despite negative biopsy, further evaluation will be warranted (Clark, et al., 2002). If the woman is post-menopausal and bleeding has not been persistent; a thin endometrial stripe in this setting is most consistent with atrophy and does not require further invasive studies. A thick endometrial stripe, persistent bleeding, or bleeding in a post- or peri-menopausal woman should be followed by additional endometrial sampling, such as hysteroscopy with curettage. In asymptomatic post-menopausal women, the decision to biopsy is also based upon a variety of factors, including cervical cytology showing endometrial cells or glandular abnormality, and risk factors for endometrial cancer, such as unopposed estrogen and tamoxifen use. In a completely asymptomatic post-menopausal woman with no risk factors and an endometrial stripe less than 5 mm, there is no need for biopsy. However, even one drop of blood in a post-menopausal woman not on hormone therapy constitutes a symptom and is an indication for biopsy.
Current evidence-based guidelines from leading medical professional organizations include no recommendation for endometrial or cervical cytology performed in conjunction with endometrial histology in the diagnostic evaluation of abnormal uterine bleeding in women suspected of having endometrial hyperplasia or endometrial carcinoma. There is insufficient evidence to support this approach.
The problems presented in existing tissue sampling devices are solved by the device and method of the present invention.